Alexander Watt

COLOURED PAPERS.

Coloured Papers.—Colouring Matters used in Paper-Making.—American Combinations for Colouring.—Mixing Colouring Materials with Pulp.—Colouring Paper for Artificial Flowers.—Stains for Glazed Papers.—Stains for Morocco Papers.—Stains for Satin Papers.

Coloured Papers.—There are several methods by which any desired shade of colour may be imparted to paper, which are as follows:—

1. By blending with the pulp in the beating-engine some insoluble substance, such as smalts blue—a kind of glass coloured by oxide of cobalt—ultramarine, yellow ochre, etc.

2. By adding a coloured liquid, which simply dyes or stains the fibre.

3. By using rags which are already coloured, in proportions to give the required shade, in which case of course the process of bleaching must be omitted.

4. By employing two substances, as yellow prussiate of potash (ferrocyanide of potassium) and a persalt of iron, for example, which, when combined, yield the requisite blue tint—Prussian blue.

By this latter method the buff shade given to what is termed toned paper is effected, by using a solution of copperas (sulphate of iron) and an alkaline solution, or by using a solution of pernitrate of iron. In experimenting in this direction we have found that a mixture of solutions of sulphate of iron and bichromate of potassa produce an agreeable and permanent buff tint. The solutions may be added to the pulp alternately, or may be first mixed and then at once put into the beater. From 2 to 3 ozs. of each salt for each gallon of water may be used if the solutions are to be mixed before using; but when applied separately the solutions may be used in a more concentrated condition.

Colouring Matters used in Paper-Making.—The following substances, used either alone or mixed in suitable proportions, are employed in colouring pulp for paper-making:—

Blue.—The coarser kind of paper used for packing is prepared from rags blued with indigo, which, when reduced to pulp, are not subjected to the process of bleaching. The finer kinds of paper are blued in various ways, but the chief material used is what is known as artificial ultramarine, of which there are many qualities in the market, to which reference is made in another chapter. Prussian blue is also used, but this is usually produced directly in the beating-engine by adding in solution, 95 parts of sulphate of iron and 100 parts of ferrocyanide of potassium (yellow prussiate of potash). Smalts blue, which was formerly much used before the introduction of artificial ultramarine, is still preferred for high-classed papers as the colour is more permanent. To obtain smalts in an exceedingly fine state of division the best plan is to grind the colour in a little water, and then to separate the finest particle by the process of elutriation, that is, by diffusing the reduced mass through a large volume of water, and after allowing the larger particles to subside, pouring off the liquor in which the finer particles are suspended, to a separate vessel, in which they are allowed to subside. If this operation is carefully conducted the smalts may be obtained in an exceedingly fine state of division, and we have found that in this state the colour blends well with the pulp, and has little or no disposition to sink through it, but produces a uniform colouring throughout.

American Combinations for Colouring.—Hofmann gives the following examples of the combination of colours which have been adopted by American manufacturers:—

Yellow Gold Envelope of fine quality is made of—

each substance being separately dissolved and added to 400 lbs. of pulp.

Orange-red Gold Envelope:—

These substances are dissolved separately and added to 400 lbs. of pulp.

Buff Envelope of fine deep shade is made from—

Some half-stuff of red jute bagging. For 400 lbs. of pulp.

Tea-Colour is made from a decoction of quercitron bark, the liquid being poured into the engine, and 2 lbs. of copperas in solution are added for every gallon of the bark extract. A little ultramarine may be used to brighten the colour.

Drab.—Venetian red, well washed, added to a pulp of tea-colour made as above will give a fine drab.

Brown is composed of several colours, or a very fine dark green tea-colour brown, containing tea, buff, drab, and ink-grey, may be made of—

The above proportions are for 400 lbs. of pulp.

The large proportion of alum prescribed in all the above examples serves as a mordant, and also, with the addition of resin soap, for sizing. All the above mixtures should be passed through a No. 60 wire-cloth into the beating-engine.

Mixing Colouring Materials with Pulp.—It will be readily understood that when paper is sized in the pulp, as Mr. Hofmann points out, the resinous alumina surrounds the fibres and prevents the colouring materials from penetrating them. In such cases the colouring materials are only loosely held, and a portion must therefore be lost in the machine. If added to the pulp before it is sized they become thoroughly mixed with the fibres, and with them enveloped by the size. The pulp should always be coloured before it is sized, except in cases where the alum or resin soap would injure the colours, or be injured by them. While the pulp is being sized and coloured, the finishing touch is given by the engine-man, who examines it and empties it into the stuff-chest.

Colouring Paper for Artificial Flowers.—Davis gives the following recipes for colouring one ream of paper of medium weight and size, sap colours only being used, and principally those containing much colouring matter. The gum arabic given in the recipes is dissolved in the sap-liquor.

Blue (dark) 1.—Mix 1 gallon of tincture of Berlin blue with 2 ozs. each of wax soap and gum tragacanth. 2. Mix ¾ gallon of tincture of Berlin blue with 2 ozs. of wax soap, and 4¼ ozs. of gum tragacanth.

Crimson.—Mix 1 gallon of liquor of Brazil wood compounded with borax, 2 ozs. wax soap and 8¾ ozs. of gum arabic.

Green.—1. Take ½ gallon of liquor of sap-green[28], 4¼ ozs. of indigo rubbed up fine, 1 oz. of wax soap, and 4½ ozs. of gum arabic. 2. ½ gallon of sap-green liquor, 4¼ ozs. of distilled verdigris, 1 oz. of wax soap, and 4½ ozs. of gum arabic.

Yellow (golden).—Mix 6½ ozs. of gamboge with 2 ozs. of wax soap.

Yellow (lemon).—1. Compound 1 gallon of juice of Persian berries with 2 ozs. of wax soap and 8¾ ozs. of gum arabic. 2. Add to 1 gallon of quercitron liquor, compounded with solution of tin, 2 ozs. of wax soap, and 8¾ ozs. of gum arabic.

Yellow (pale).—Mix 1 gallon of fustic, 2 ozs. of wax soap, and 8¾ ozs. gum arabic.

Yellow (green).—Compound 1 gallon of sap-green liquor with 2 ozs. each of distilled verdigris and wax soap, and 8¾ ozs. of gum arabic.

Red (dark).—1 gallon of Brazil-wood liquor, 2 ozs. of wax soap, and 8¾ ozs. of gum arabic.

Rose Colour.—Mix 1 gallon of cochineal liquor with 2 ozs. of wax soap, and 8¾ ozs. of gum arabic.

Scarlet.—1. Mix 1 gallon of Brazil wood liquor compounded with alum and a solution of copper, with 2 ozs. of wax soap, and 8¾ ozs. of gum arabic. 2. Mix 1 gallon of cochineal liquor compounded with citrate of tin, with 2 ozs. of wax soap, and 8¾ ozs. of gum arabic.

Stains for Glazed Papers.—Owing to the cheapness of these papers glue is used in lieu of the more expensive gums; 1 lb. of glue dissolved in 1¼ gallon of water; the proportions of colouring materials are given for 1 ream of paper of medium weight and size.

Black.—1. Dissolve 1 lb. of glue in 1¼ gallon of water; triturate this with lampblack (1 lb.) previously rubbed up in rye whiskey; Frankfort black, 2¾ lbs.; Paris blue, 2 ozs.; wax soap, 1 oz.; then add liquor of logwood, 1½ lb. 2. 1½ gallon of liquor of logwood compounded with sulphate of iron, 1 oz. of wax soap, and 4½ ozs. of gum arabic.

Blue (azure).—1¼ gallon of glue liquor, as before, mixed with 1½ lb. Berlin blue, 2¾ lbs. powdered chalk, 2¼ ozs. of light mineral blue, and 2 ozs. of wax soap.

Blue (dark).—Mix with 1¼ gallon of glue liquor, 4½ lbs. of powdered chalk, 4¼ ozs. of Paris blue, and 2 ozs. of wax soap.

Blue (pale).—1. Mix ½ gallon of tincture of Berlin blue and 1 oz. of wax soap with 3½ ozs. of solution of gum tragacanth. 2. Take 1¼ gallon of glue liquor and mix with 4 lbs. of powdered chalk and 2 ozs. each of Paris blue and wax soap.

Brown (dark).—1. 1¼ gallon of glue liquor, mixed with 6 lbs. each of colcothar (jewellers' rouge) and English pink, 1½ lb. of powdered chalk, and 2 ozs. of wax soap. 2. Dissolve 1 oz. of wax soap and 4½ ozs. of gum arabic in ½ gallon of good Brazil-wood liquor, and add a like quantity of tincture of gallnuts.

Green (copper).—Mix in 1¼ gallon of glue liquor 4 lbs. of English verdigris, 1½ lb. of powdered chalk, and 4 ozs. of wax soap.

Green (pale).—Mix with 1¼ gallon of glue liquor 1 lb. of Bremen blue, 8½ ozs. of whiting, 1 oz. of pale chrome yellow, and 2 ozs. of wax soap.

Lemon Colour.—Mix in 1¼ gallon of glue liquor 13 ozs. of lemon chrome, 2 lbs. of powdered chalk, and 2 ozs. of wax soap.

Orange-Yellow.—Mix in 1¼ gallon of glue liquor 2 lbs. of lemon chrome, 1 lb. of Turkish minium, 2 lbs. of white lead, and 2 ozs. of wax soap.

Red (cherry).—Mix in 1¼ gallon of glue liquor 8½ lbs. of Turkey red, previously mixed up with ¼ gallon of Brazil-wood liquor, and 2 ozs. of wax soap.

Red (dark).—Mix ¾ gallon of Brazil-wood liquor with wax soap 1 oz., and gum arabic 4½ ozs.

Red (pale).—To 1¼ gallon of glue liquor is to be added 8¼ lbs. of Turkey red previously rubbed up with 2 ozs. of wax soap.

Violet.—4½ ozs. of gum arabic, and 1 oz. of wax soap are to be mixed with ½ gallon of good logwood liquor. When the gum is dissolved, mix with it enough potash to form a mordant.

Stains for Morocco Papers.—For 1 ream of paper of medium size and weight the following recipes are recommended:—

Black.—8¾ ozs. of good parchment shavings are dissolved in 1½ gallon of water; into this liquid is to be stirred lampblack, 1 lb., Frankfort black, 3 lbs., and Paris blue, 1¾ oz.

Blue (dark).—Dissolve parchment shavings, as before, and mix in 8¼ lbs. of white lead and 4½ lbs. of Paris blue.

Blue (light).—Dissolve parchment shavings, as before, and mix in 8¾ lbs. of white lead and 2¼ ozs. of Paris blue.

Green (dark).—Dissolve 13 ozs. of parchment shavings in 2½ gallons of water, and mix in 10 lbs. of Schweinfurth green.

Green (pale).—Prepare solution of parchment as in the last, and mix with 8¾ lbs. of Schweinfurth green and 1 lb. of fine Paris blue.

Orange-Yellow.—8¾ ozs. of parchment shavings are to be dissolved in 1½ gallon of water, and then mixed with 1½ lb. of lemon chrome, 8¾ ozs. of orange chrome, and 1 lb. of white lead.

Red (dark).—To the same quantity of parchment liquor as the last is to be added 7¾ lbs. of fine cinnabar, and 1 lb. of Turkey red.

Red (pale).—To the same quantity of parchment liquor add 8¾ ozs. of Turkey red.

Violet (light).—To 1½ gallon of parchment liquor add 4¼ lbs. of white lead, 13 ozs. of light mineral blue, and 8¾ ozs. of scarlet lake.

Violet (dark).—To 1½ gallon of parchment liquor add 3¾ lbs. of white lead, 1 lb. of pale mineral blue, and 8¾ ozs. of scarlet lake.

Yellow (pale).—To 1½ gallon of parchment liquor add 2 lbs. of light chrome yellow and 8¾ ozs. of white lead.

Stains for Satin Papers.—For each ream of paper of medium weight and size the following recipes are given:—

Blue (azure).—13 ozs. of parchment are dissolved in 2½ gallons of water and mixed with 3 lbs. of Bremen blue, 1¾ lb. of English mineral blue, and 4½ ozs. of wax soap.

Blue (light).—8¾ ozs. of parchment are to be dissolved in 1½ gallon of water, and to be mixed with light chrome yellow, 13 ozs.; colcothar, 6½ ozs.; Frankfort black, 2 ozs.; powdered chalk 3 lbs., and wax soap, 3½ ozs.

Brown (reddish).—1½ gallon of parchment liquor as the last, to which is added yellow ochre, 1 lb.; light chrome yellow, 4½ ozs.; white lead, 1 lb.; red ochre, 1 oz., and wax soap, 3½ ozs.

Brown (light).—1½ gallon of parchment liquor, as before, to which is added 13 ozs. of light chrome yellow, 6½ ozs. of colcothar, 2 ozs. of Frankfort black, 3 lbs. of powdered chalk, and 3½ ozs. of wax soap.

Grey (light).—1½ gallon of parchment liquor is mixed with 4¼ lbs. of powdered chalk, 8¾ ozs. of Frankfort black, 1 oz. of Paris blue, and 3½ ozs. of wax soap.

Grey (bluish).—To the above quantity of parchment liquor add 4¼ lbs. of powdered chalk, 1 lb. of light mineral blue, 4¼ ozs. of English green, 1¾ oz. of Frankfort black, and 3½ ozs. of wax soap.

Green (brownish).—To the same quantity of parchment liquor add Schweinfurth green, 1 lb.; mineral green, 8¾ ozs.; burnt umber and English pink, of each 4¼ ozs.; whiting, 1 lb., and wax soap, 3½ ozs.

Green (light).—To the same quantity of parchment liquor add English green and powdered chalk, of each 2¾ lbs., and 3½ ozs. of wax soap.

Lemon Colour.—To the same quantity of parchment liquor add lemon chrome, 1½ lb.; white lead 1 lb., and wax soap, 3½ ozs.

Orange-Yellow.—Parchment liquor as before, 1½ gallon, to which is added lemon chrome, 4¼ lbs.; Turkey red, 8¾ ozs.; white lead, 1 lb., and wax soap, 3½ ozs.

Rose Colour.—1½ gallon of parchment liquor as before, to which is added ¾ gallon of rose colour prepared from Brazil wood and chalk, and 6½ lbs. of wax soap.

Violet (light).—1½ gallon of parchment liquor as above, mixed with light mineral blue and scarlet lake, of each 1½ lb.; white lead, 1 lb., and wax soap, 3½ ozs.

White.—To 1½ gallons of parchment liquor is added fine Kremnitz white, 8¾ lbs., Bremen blue, 4¼ ozs., and wax soap, 3½ ozs.

Silver White.—1½ gallon of parchment liquor mixed with Kremnitz white, 8¾ lbs., Frankfort black, 8¾ ozs., and wax soap, 3½ ozs.

Pale Yellow.—1½ gallon of parchment liquor, to which is added 4½ lbs. of light chrome yellow, 1 lb. of powdered chalk, and 3½ ozs. of wax soap.